If it were mine......

Not a lot of torque is requried to move a throttle (provided there is no binding in the linkage), however, being mounted so close to a vibrating 2 stroke, there will be a lot of shaking transferred both through the linkage, as well as through the structure that the servo is mounted on....so you need something that will provide some endurance. I'd probably go for a 81 or 85 metal geared servo, or maybe the 225. depending on space and weight restrictions. I need to point out that I haven't used any of these servos in this application, but would be willing to give it a try, and would not hesitate to to swap them out if they were not up to the task. Plan B would be standard servos as they have proven they can handle the job in thousands of trainers over many years of service.....

Beauty of this hobby is that everyone does things a little bit differently, and you can learn from everyone.....